Assertion : The `HF_(2)^(-)` ion exists in the solid state & also in liquid state but not in aqueous state.
Reason : The magniture of hydrogen bonds among HF molecules is weaker than that in between `HF and H_(2)O`.

Options

A. If assertion is true but the reason is false
B. If assertion is false but reason is true
C. If both assertion and reason are true and the reason is the correct explanation of assertion
D. If both assertion and reason are true and the reason is not the correct explanation of assertion

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that the `HF2^(-)` ion exists in the solid and liquid states but not in the aqueous state.

- **Solid State**: In the solid state, `HF2^(-)` can exist due to strong hydrogen bonding between the `HF` molecules, allowing the formation of a stable structure.
- **Liquid State**: In the liquid state, `HF2^(-)` can also exist because the molecules can still interact through hydrogen bonding, though the arrangement may be less ordered than in the solid state.
- **Aqueous State**: In the aqueous state, `HF2^(-)` does not exist because when `HF` is mixed with water, it tends to dissociate into `H3O^+` and `F^-` ions, preventing the formation of `HF2^(-)`.

### Step 2: Understanding the Reason
The reason states that the magnitude of hydrogen bonds among `HF` molecules is weaker than that between `HF` and `H2O`.

- **Hydrogen Bonding in HF**: The hydrogen bonds between `HF` molecules are significant but not as strong as those formed between `HF` and `H2O`.
- **Hydrogen Bonding with Water**: When `HF` is in the presence of water, the ability of water to form hydrogen bonds is stronger due to its high polarity and ability to stabilize ions, leading to the formation of `H3O^+` and `F^-` instead of `HF2^(-)`.

### Step 3: Conclusion
Both the assertion and the reason are true. The reason correctly explains why `HF2^(-)` does not exist in the aqueous state, as the stronger hydrogen bonding with water leads to the dissociation of `HF`.

### Final Answer
Both the assertion and the reason are true, and the reason is a correct explanation of the assertion.

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